class Utils
{
    const UTC_TIME_ZONE = 'UTC';
    const DATETIME_FORMAT = 'Y-m-d H:i:s';

    /**
     * Returns UTC `DateTime` string
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return string
     */
    public static function getCurrentUTCDateTimeString() {
        return self::getCurrentUTCDateTime()->format(self::DATETIME_FORMAT);
    }

    /**
     * Returns UTC `DateTime`
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return DateTime
     */
    public static function getCurrentUTCDateTime() {
        return (new DateTime('now', new DateTimeZone(self::UTC_TIME_ZONE)));
    }

    /**
     * Returns data for all Welcart items that have a post type of 'published'
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \wpdb $wpdb
     * @return array
     */
    public static function getAllPublishedWelcartItems() {
        global $wpdb;

        $welitems = [];
        $itemt = usces_get_tablename('usces_item');
        $query = $wpdb->prepare(
            "SELECT posts.ID
            FROM $wpdb->posts AS posts
            JOIN $itemt AS itemt ON itemt.post_id = posts.ID
            WHERE post_status = %s",
            'publish'
        );
        $allitems = $wpdb->get_col($query);
        if (!empty($allitems)) {
            foreach ($allitems as $alli_post_id) {
                $welitem = self::getWelItemData($alli_post_id);
                if (!empty($welitem)) {
                    $welitems[] = $welitem;
                }
            }
        }

        return $welitems;
    }

    /**
     * Gets and adds extra meta data to a `welitem` array and returns it
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param int $post_id
     * @return array
     */
    public static function getWelItemData($post_id) {
        $welitem = wel_get_product($post_id);
        if (!empty($welitem)) {
            $mainpictid = '';
            if (is_array($welitem['itemPicts']) && !empty($welitem['itemPicts'][0])) {
                $mainpictid = (int)$welitem['itemPicts'][0];
            }
            foreach ($welitem['_sku'] as $index => $sku) {
                $pid = $mainpictid;
                if (!empty($sku['pict_id'])) {
                    $pid = (int)$sku['pict_id'];
                }
                $welitem['_sku'][$index]['images'] = [
                    'fullSizeLink' => !empty($pid) ? wp_get_attachment_image_src($pid, 'full-size', true) : '',
                    'mediumSizeLink' => !empty($pid) ? wp_get_attachment_image_src($pid, 'medium', true) : '',
                    'thumbnailLink' => !empty($pid) ? wp_get_attachment_image_src($pid, 'thumbnail', true) : '',
                ];
            }
        }

        return $welitem;
    }

    /**
     * Gets data for an SKU
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \wpdb $wpdb
     * @param int $skuMetaId
     * @return array
     */
    public static function getSkuData($skuMetaId) {
        global $wpdb;

        $sku_table = usces_get_tablename('usces_skus');
        $res = $wpdb->get_row(
            $wpdb->prepare(
                "SELECT * FROM {$sku_table} WHERE meta_id = %d",
                $skuMetaId
            ),
            ARRAY_A
        );
        if (empty($res)) {
            return [];
        }

        $welitem = new \Welcart\ItemData($res['post_id']);
        if (empty($welitem)) {
            return [];
        }

        $product = $welitem->get_product();
        $sku = $welitem->get_sku_by_id($skuMetaId);
        if (empty($sku)) {
            return [];
        }

        $pictid = '';
        if (is_array($product['itemPicts']) && !empty($product['itemPicts'][0])) {
            $pictid = (int)$product['itemPicts'][0];
        }
        if (!empty($sku['pict_id'])) {
            $pictid = (int)$sku['pict_id'];
        }
        $sku['images'] = [
            'fullSizeLink' => !empty($pictid) ? wp_get_attachment_image_src($pictid, 'full-size', true) : '',
            'mediumSizeLink' => !empty($pictid) ? wp_get_attachment_image_src($pictid, 'medium', true) : '',
            'thumbnailLink' => !empty($pictid) ? wp_get_attachment_image_src($pictid, 'thumbnail', true) : '',
        ];

        return [
            'item' => $product,
            'sku' => $sku,
        ];
    }

    /**
     * Checks whether an SKU exists and returns its post ID
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \wpdb $wpdb
     * @param int $skuMetaId
     * @return GenericError|int post ID if exists
     */
    public static function getSkuPostId($skuMetaId) {
        global $wpdb;

        $sku_table = usces_get_tablename('usces_skus');
        $postId = (int)$wpdb->get_var(
            $wpdb->prepare(
                "SELECT post_id FROM {$sku_table} WHERE meta_id = %d",
                $skuMetaId
            )
        );
        if ($postId < 1) {
            return Master::getErrorStore()->getErrorResponse(
                ErrorStore::SKU_NOT_FOUND,
                [$skuMetaId],
                [],
                [$skuMetaId]
            );
        }

        return $postId;
    }

    /**
     * Returns `true` if the SKU is a group item in any combo-sets, `false` otherwise
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \wpdb $wpdb
     * @param int $skuMetaId
     * @return bool
     */
    public static function isGroupItem($skuMetaId) {
        global $wpdb;

        $csgit = Schema::getComboSetGroupItemsTable();
        return (bool)(int)$wpdb->get_var(
            $wpdb->prepare(
                "SELECT COUNT(ID) FROM {$csgit} WHERE welitem_sku_meta_id = %d",
                (int)$skuMetaId
            )
        );
    }

    /**
     * Returns full size and thumbnail size SKU image. Defaults to item image if no
     * SKU image was found.
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param int $skuMetaId
     * @return string[]
     */
    public static function getSkuImageLinks($skuMetaId) {
        global $wpdb, $usces;

        $defaultres = [
            'fullSizeLink' => '',
            'thumbnailLink' => '',
        ];

        $data = $wpdb->get_row(
            $wpdb->prepare(
                "SELECT * FROM {$wpdb->postmeta} WHERE meta_id = %d AND meta_key = '_isku_'",
                (int)$skuMetaId
            ),
            ARRAY_A
        );

        if (empty($data)) {
            return $defaultres;
        }

        $skudata = unserialize($data['meta_value']);
        if (empty($skudata)) {
            return $defaultres;
        }

        $imgid = $usces->get_subpictid($skudata['code']);
        if (empty($imgid)) {
            $imgid = $usces->get_mainpictid($usces->getItemCode($data['post_id']));
        }

        $imgid = !empty($imgid) ? $imgid : 0;

        return [
            'fullSizeLink' => wp_get_attachment_image_src($imgid, 'full-size', true),
            'mediumSizeLink' => wp_get_attachment_image_src($imgid, 'medium', true),
            'thumbnailLink' => wp_get_attachment_image_src($imgid, 'thumbnail', true),
        ];
    }
}